Safety device



March 26, 1940.

A. J. REILLY SAFETY DEVICE Filed Aug. 4. 1938 2 Sheets-Sheet 1 A. J. REILLY 2,195,014

SAFETY DEVICE Filed Aug. 4, 1958 2 Sheets-Sheet 2 Patented Mar. 26, 1940 more!) 5mm l ".9 Claims.

This invention relates to safety devicesa'od more particularly to safety devices for 'pre sses'or the like. l l i I It is the principal object of this invention to provide a. simple and effective safety device for a press or the like which provides a high degree of protection to the operator at all times during the operation when danger exists.

A further object is to provide a safety device such that the operator who takes a normal position at the controls will be in a'safe position for the operation to be performed, the device being at once effective to stop the operation at any stage if the operator leaves-the controls.

A further object is to provide a safety device which'combines a high egreeof protection for the operator with abrakingaction during the return stroke of the machine.

A further object is to provide a device which operates with a very smalladditional load on the machine during the working stroke, but which provides an increased load and a resulting braking actionduring the return stroke, the braking action increasing near stroke.

Other objects andadvantages will be apparent from the accompanying drawings, the following description, and. the appended "claims;

In the drawings, inwhich a preferred embodiment of the invention is shown for purposes of illustration,

Fig. 1 is a front elevational view showing a press having attached thereto the device of the the end of the return present invention;

Fig. 2 is a longitudinal central sectional View on an enlarged scale of the device;

Fig. 3-is a transverse sectional view' taken on the line 3-3 of the Fig. 2;

Fig. 4 is a transverse sectional view taken on g parts of the press so that control of the parts of:

the safetydevice' will in turn control 'thepress parts.

the line 6-4 of Fig. 2; v v

Fig. 5 is a fragmentary view in the nature of a perspective and showing the control members fitted to the top of the device;

Fig. 6 is a fragmentary longitudinal sectional view of one end of a device and showing a modification. p

The device offthe present invention provides a safety device which is effective independently of the usual stop and trip mechanismfwith which presses are equipped, the device when actuated serving to stop the press whether or not these other mechanisms are functioning properly. Furthermore, the presentinvention is efiective'to stop the press immediatelyat any time during the dangerous portions of the press operation :upon

release-of the controls by the operator. Andthe 1 device operates in this manner to stop the press during any succeeding cycle ofoperations which may follow for any reason, as well as upon the initial stroke."

'There is thus provided a other apparatus or by inadvertence of 'theopra-I safety device which affords protection r to the operator both'on the initial stroke .andon any succeeding strokes which may occur, whether caused by failure' of g 1'0" tor, since failure of other apparatus cannot affect PATENT OFFIQE the entirely independent safety device, and since I in the event of inadvertence, operation can only continue if'the operator remains at the controls.

Finally, the safety device of the-present invention acts positively to stop. the press, "rather-than merely to block off for'shield the press parts at cer, Consequently tain times in the operating cycle. there is .no way in which the operator-can circumvent the operation of the device by" developing new and dangerous operating habits.

The present 'inventionmakes possible all these advantages, and in addition provides for a de-'-' sirable braking action on the return stroke of the press to properly cushion the' rnoving parts thereof. l I r Referring now to the drawings in detail, which disclose a perferred embodimentof the invention,

ill indicates generally a press equipped with the device of the present invention. Thepress 'lll :comprises a frame H having a bed l2 formed thereon, and-a slide l4 reciprocablymountedin frame I! for cooperation withthe bed. l2. Suitable means for reciprocating the slidel l are provided, including crank shaft l5 and connecting rod. l8, driven from a suitable powersource.

The safety device, indicated g'enerallyatZfl,

comprises fixed and movable parts whichare I adapted, to beattached to the fixed, and movable As illustrated, safety device-20"includes a body portion 2i which is rigidly secured'to press frame ll, and'a movable connecting rod 22 having an arm 23 adjustably secured'thereto, the arm 23 being rigidly attached to press slide M for movement therewith.

Safety device 211 has an outer-cylinder 25 which forms part of the body portion 2| of the device;

and cylinder heads 21 and 28 are attach'edthereto influid tight relationship, the parts'being" secured together by through bolts 29. Cylinder heads 21 and 28 are provided with suitable to press frame H. v r

integrally formed brackets 3| and 32 for attachment An inner cylinder 34 is concentrically mounted within outer cylinder 25, and is of a size to provide an annularly shaped space or channel 35 beinterior of inner cylinder 34 on opposite sides of said piston.

The entire assembly is adapted to contain liquid, and the construction is such that upon movement of piston 3'! liquid can flow out one set of ports, along channel 35, and in the other set of ports.

Piston 3'! has connecting rod 22 attached thereto as by threads 15, and extending through aperture 45 in cylinder head 21, suitable packing means 4'! being provided to form a liquid tight connection. Piston 31 has a stroke equal to the travel of slide M of press H). Cylinders 25 and 34 are made somewhat longer than the stroke of the piston, and the piston is so adjusted that at the top of its travel it is in line with ports 38, as best shown in Fig. 2, whereas at the bottom of its travel, it preferably stops short of ports 38, thus making possible at all times a free flow of liquid through ports 38 while providing for restriction of flow through ports 39 during certain parts of the stroke. In order that piston 31 may properly cooperate with ports 39, the piston is formed with a depth sufficient so that it can completely close ports 39 when the piston and ports are in alignment.

The proportioning of the parts is such that, the device being filled to the desired level with liquid, the piston travels its downward stroke with a low resistance being offered by the liquid, whereas on the up stroke, the flow of liquid will offer increased resistance to the movement of the piston and consequently a differential braking action will be exerted on the press. This is accomplished by making the area of ports 38 sub stantially equal to the effective cross sectional area of the lower face 50 of piston 31. Thus as piston 31 moves downwardly, its lower face presents to the liquid at pressure exerting area of substantially the same size as the total area of ports 38, and thus the ports ofier substantially no restriction to the flow of liquid. The effective cross sectional area of the annular space 35 is likewise made substantially equal to or somewhat greater than the total area of ports 38, and therefore also to the effective cross sectional area of cylinder 34. Thus liquid forced out of inner cylinder 34 by downward movement ofpiston 3'! may pass along the space or bypass means 35 substantially without restriction of flow. Similarly ports 33 are given substantially the same total area as ports 38 and consequently these likewise offer little or no restriction to the flow, and therefore liquid displaced by the underface 50 of the piston flows out ports 38, along bypass 35 and in ports .39 with minimum resistance to the flow.

0n the'return stroke, however, the upper face 53 of piston 31 presents a larger pressure producing area to the liquid than lower face 50, since there is no connecting rod on this side of the piston. Thus upon upward movement of the piston, the displaced liquid is forced through the ports 39 at a'more rapid rate in proportion to the pistonspeed, and the size of these ports, as just described, is such as to offer increased resistance to the flow of liquid, and thus assert a differential braking action upon the return stroke of the the press. The ports 38 and 39 are preferably radially arranged, as indicated particularly in Fig. 4, having eight equally spaced ports of equal size.

The arrangement of the parts as shown provides for additional braking action near the end of the return stroke of piston 31. As piston 31 approaches its top position in which it closes ports 39, the piston increasingly cuts on" portions of the ports 39, thus progressively decreasing the total port area available for the expulsion of liquid, and consequently increasing the resistance to the flow and therefore to the movement of the piston 37 and slide 14. As a result, the speed of slide i4 is increasingly reduced as it approaches its top position, and consequently there is less work to be done by the standard braking mechanism of the press, since at the time the stop mechanism operates, the speed of the parts has been greatly reduced by the braking action of other hand, if it is preferred to retain the conventional brake, it may be adjusted to assert less braking action than would be needed without the safety device, with a resulting decrease in wear.

Control means are provided forgoverning the flow of liquid through ts 38 and 39 and bypass means 35. As illustrated these means take the form of a. valve 55 of disk or wheel-like shape and slidably mounted in the top of inner cylinder 34. Valve 55 has a depth of face in excess of the longitudinal dimensions of ports 39, so that in its lowermost position it will overlie these ports and shut off the flow of liquid therethrough. As best shown in Fig. 3 valve 55 has a series of cylindrical bores 56 formed therein, and in the embodiment shown six of these bores are used these being arranged in symmetrical radial position. Each of the bores 56 contains a spring 51', and these springs serve to move the valve to closed position, their upper ends bearing upon the inmeans 64 being provided to .form a liquid tight connection. Valve stem has a shoulder mem ber 65 attached to its upper end. Screw 56 carrying locking nut 61 is' threadedly received by a laterally projecting portion of shoulder member 65, and cooperates with top member 28 to provide an adjustable stop limiting the downward travel of valve 55. In order that the valve may function regardless of the fluid pressures within the device, the bottom face of'the valve is apertured at 68, there being a series of apertures 68 each located concentrically with one of the bores 56, but of smaller diameter to provide a shoulder for the bearing of spring 51. Apertures 68 and bores 55 together thus provide free communicaticn between the opposite sides of the valve 55.

Safety control. handles are provided for raising valve 55 to its upper position in which ports 39 are open and movement of piston 31 can take place. As shown, two control levers are provided for the operation of valve 55, and these are so arranged that the operator must actuate both levers in order to operate valve 55. Referring particularly to Fig. 5, outwardly extending lever "H is pivotally mounted in clevis 12 formed in the upper end of shoulder member 65. Downwardly extending lever 14 is fixedly secured to cross shaft 75 which is journalled in upstanding members 16 formed on cylinder head 28. Cross shaft I5 has fixedly attached thereto a forwardly extending link 18, and the forward end of link 18 is connected to lever H by link 8|. Thus the movement of either handle alone will merely produce a movement of the other handle, but will not serve to actuate valve 55. When both handles are pulled, however, or when one handle is held from movement and the other pulled, connecting rod 6!! is raised and valve 55 opened.

Thus, if lever 14 is held stationary, thenthe I upper end of link 8! becomes the fulcrumfor lever 1|,and upon depressing the outer end of lever H, valve stem 60 is raised and valve 55 opened. The levers are thus seen to be fulcrumed one upon the other. It is convenient to interconnect some part of the control lever mechanism to press trip 90 so that it may be actuated simultaneously with the opening of valve 55, since both the operators hands are needed for the actuation of levers H and 14. As illustrated, shaft 15 is extended to press trip 90, and serves to actuate it.

The operation of the safety device will in the main be clear from the above description. The operation of the press is initiated by manipulating levers H and 14 to hold the valve 55 in open position and also 'to actuate the strip 90. The operator must then hold levers H andllin operating position throughout the operation of the press, since if he at any time releases either lever, valve 55 will close, and the press will at once come to a stop. The down strokeis completed with the safety device oiferinga low resistance because of the substantially unrestricted flow of liquid through the various parts, Upon the commencement of the upstroke the device exerts the above described differential braking action upon the press slide, and as the return stroke near completion, so that piston 31 begins to close off ports 39, an increased braking action results, and the press is still further slowed so that the stop mechanism and brake,'if used, can easily function. In the event that the stop mechanism fails to function, the press can only repeat if the operator is still depressing levers H and 14, in which case hewill be in a position of safety. If, however, he has removed his hands the press will at once stop, and consequently cannot cycle or repeat in spite of the failure of the stop mechanism. When the press is stopped in midstroke by the operation of the safety device, there is effected a rapid but cushioned stopping because of the presence of a small amount of air in the device which is compressed to cushion the stop.

The liquid used, preferably a suitable oil, is supplied to the interior of the device by means of plug 95 in cylinder head 28, communicating with one of the bores 56. By filling at this point, there is provided an air trap at the upper part of space 35, and the air so entrapped provides the cushioning effect for a suitable emergency stop. It will be noted that the amount of braking action secured may be slightly modified by the position of the parts at the time of filling. Thus if the piston is in its upper position when filled,

alesser quantity of fluids will be introduced than when the piston is 'inits lowermost position, the difference being the volume of the piston rod. This provides for varying the degree of braking ing action is desired, provision may be made for filling the device under pressure.

In Figfiythere is shown a modification of the device in. which the apparatus functions as a safety device only on the downstroke, and in which the press will return'to its upper position whether the operating handles are actuated or not. In order to obtain this result, the bottom of valve 55 is formed as an imperforate surface, apertures 68 being omitted. The area above valve 55' and including bores 56' is vented to atmosphere by means of vent 91, thus preventing the existence of pressure conditions which might interfere with the operation of valve 55. Filling is accomplished by means of removable plug 98 communicating directly with space or bypass 35. The operation of the embodiment shown in Fig. 6 is in all respects the same as that shown in the force developed. If additional variation in brakother embodiment except that, as mentioned generated by piston 31 on its upstroke serves to impinge upon the imperforate bottom face' of valve 55', and raises it thus exposing ports 38' and allowing liquid to flow out and the piston 37' to return to its top position.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope'of' the invention which is defined in the appended claims.

What is claimed is:

l. A safety device for a power operated machine such as a press having power drive means for actuating a movable part comprising a cylinder mounted on the frame of said machine, a piston of said fiuid flow, valve means for closingsaid ports and. thus stopping fluid circulation and causing stoppage of movement of said piston,

resilient means for normally urging said valve,

means to a position to close said ports, and manualrelease means for opposing said resilient means-and maintaining said valve in open position, said valve closing upon release of said manual means to immediatelycheck -movement of said movable machine part independently of said power drive means.

2.- A safety device for a power operated machine such as apress having power drive means for actuating a-movable part comprising a cylinder mounted.onthe frame of said machine, apiston movable in said cylinder and attached to the movable part of said machine, a fluid circulating system associated with-said cylinder and with said piston, ports formed in the wall of saidcylinder in the path of said 'fiuid flow-and positioned.

said: piston as it approaches its uppermost position being effective to increasingly reduce the outlet area of said ports and impede the flow of fluid"therethrough and'produce an increasing braking effect uponsaid piston, valve meansfor closing said ports and thus stopping fluid circulationand causing stoppage of movement of said piston, resilient means for normally urging said valve means to a position to close said ports, and manual release means for opposing said resilient means and maintaining said valve in open position, said valve closing upon release of said manual means to immediately check movement of said movable machine part independently of said power drive means.

3. A safety device for a power operated machine such as a press having power drive means for actuating a movable part comprising a cylinder mounted on the frame of said machine, a piston movable in said cylinder and attached to the movable part of said machine, a fluid circu lating system associated with said cylinder and with said piston, ports formed in the wall of said cylinder in the path of said fluid flow and positioned in alignment with the uppermost position of said piston, the wall of said piston being of suflicient extent to completely cover and close off said ports when said piston is-in its uppermost position, said piston as it approaches its uppermost position being effective to increasingly reduce the outlet area of said ports and impede the flow of fluid therethrough and produce an increasing braking efiect upon said piston, valve means slidably mounted within said cylinder and movable downwardly when said ports are not covered by said piston to a position in alignment with and closing said ports to stop fluid circulation and cause stoppage of movement of said piston, said valve also being movable upwardly to a position clear of said ports and beyond the path of travel of said piston, resilient means for normally urging said valve means to a position to close said ports, and manual release means for opposing said resilient means and maintaining said valve in open position, said valve closing upon release of said manual means to immediately check movement of said movable machine part independently of said power drive means. i

4. A safety device for power operated machines such as a press having power drive means for actuating a movable part comprising a cylinder mounted on the frame of said machine, a piston movable in said cylinder and attached to the movable part of said machine, a piston rod connected to said piston and passing through one end of said cylinder whereby said piston displaces a smaller volume of liquid when moved toward the connecting rod receiving cylinder end than when moved in the opposite direction, a fluid circulating system associated with said cylinder and said piston, port means in said cylinder side wall in the path of said fluid flow and located adjacent the rod receiving cylinder end, said port means having an area substantially equal to the cross-sectional area of said cylinder less the cross-sectional area of said connecting rod, additional port means located in said cylinder wall and adjacent the opposite end thereof and having an area substantially equal to said firstnamed port means, said fluid circulating means having a cross-sectional area at least as large as said ports, valve means for closing said secondnamed port means and thus stopping fluid circulation and causing stoppage of movement of said piston, resilient means for normally urging said valve means to a position to close said ports, and manual release means for opposing said resilient means and maintaining said valve in open position, said valve closing upon release of said manual means to immediately check movement of said movable machine part independently of said power drive means.

5. A safety device for a power operated machine such as a press having power drive means for actuating a movable part comprising a cylinder mounted on the frame of said machine, a piston movable in said cylinder and attached to the movable part of said machine, a fluid circulating system associated with said cylinder and said piston, ports in said cylinder in the path of said fluid flow, valve means slidably mounted within said cylinder above said piston and movable to a position in alignment with and closing said ports to stop fluid circulation and cause stoppage of movement of said piston, said valve means also being movable to a position clear of said ports, resilient means for normally urging said valve means to a position to close said ports, and manual release means for opposing said resilient means and maintaining said valve in open position, said valve closing upon release of said manual means to immediately check movement of said movable machine part independently of said power drive means.

6. A safety device for a power operated machine such as a press having power drive means for actuating a movable part comprising a cylinder mounted on the frame of said machine, a piston movable in said cylinder and attached to the movable part of said machine, a fluid circulating system associated with said cylinder and said piston, ports in said cylinder in the path of said fluid flow, valve means slidably mounted within said cylinder above said piston and movable to a position in alignment with and closing said ports to stop fluid circulation and cause stoppage of movement of said piston, said valve means also being movable to a position clear of said ports and being formed with apertures ex tending therethrough to provide balanced pressure conditions on both sides of said valve providing for operation of said valve independently of the direction of piston movement, resilient means for normally urging said valve means to a position to close said ports, and manual release means for opposing said resilient means and maintaining said valve in open position, said valve closing upon release of said manual means to immediately check movement of said movable machine part independently of said power drive means.

'7. A safety device for a power operated machine such as a press having power drive means for actuating a movable part comprising a cylinder mounted on the frame of said machine, a piston movable in said cylinder and attached to the movable part of said machine, a fluid circulating system associated with said cylinder and said piston, ports in said cylinder in the path of said fluid flow, valve means slidably mounted within said cylinder above said piston and movable to a position in alignment with and closing said ports to stop fluid circulation and cause stoppage of movement of said piston, said valve means also being movable to a position clear of said ports and being formed with an imperforate body portion to provide for lifting of said valve away from closed position by the fluid upon upward movement of said piston and provide for completion of the upward stroke of said piston, resilient means for normally urging said valve means to a-position to close said ports, and man- 'ual release means for opposing said resilient means and maintaining said valve in open position, said valve closing upon release of said manual means to immediately check movement of said movable machine part independently of said power drive means. i I

8; A safety device fora power operated ma chine such as a press having power driven means for actuating a movable part comprising a cylinder mounted on the frame of said' machine,

a piston movable in said cylinder and attached w to the movable part of said machine, a fluid circulating system associatedwith said cylinder and with said piston, ports in saidcylinder in the path of said fluid flow, valve means for closing said ports and thus stopping fluid circulation and causing stoppage of movement of said piston, re-

silient means for normally urging said valve to immediately check movement of said movable machine part independently of said power drive means. l

. able machine'part'to 9. A safety device for a power operated machine such as a press having power drive means "for actuating a movable part comprising acylinder mounted on the frame ofv said machine,

a piston movable in said cylinder and attached Y to the movable part of said machine, a fluid circulating system associated with said cylinder and with said piston and containing'a major portion of liquid and a minor predetermined amount of air trappedabove'said liquid, ports in'said cylinder in the path of said fluid flow, valve'means for closing said'ports and'thus stopping fluid circulation and causing stoppage of movement of said piston, resilient means for normallyurging said valve means to a position to, close said ports,

v and manual release means for opposing said resilient means and maintaining said valve .in open position, said valve closing upon release of said 7 manual means REILLY;

v to immediately check movement I of said'movable machine part independentlyof said power drive means and to compress the'air in said circulating system and bring said mov.-

a rapid cushioned stop. 

